Hi,
The problem might be mode of the vector "r". Try this
D[,as.character(r)=="1"]
But I am not sure that is the problem. Sometimes "factors" tend to
complicate things. Look for "factor" in the R FAQ page.
Ritwik.
On 9/20/06, David Barron <[EMAIL PROTECTED]> wrote:
> You don't need a loop. Yo
You don't need a loop. You could try
> r <- c(0,0,1,1)
> matD <- matrix(1:12,nrow=3)
> matD
[,1] [,2] [,3] [,4]
[1,]147 10
[2,]258 11
[3,]369 12
> matD[,r==1]
> matD[,r==1]
[,1] [,2]
[1,]7 10
[2,]8 11
[3,]9 12
On 20/09/06, Y
Hello,
I am not very familiar with R and need help in deleting a few columns in a
matrix.
Suppose I have a indicator variable called r and it's defined as r = (0, 0,
1, 1). A matrix D is a 3X4 matrix. If I want a new matrix which contains
only the columns of D corresponding to the elements of
